In lenticular type 3-D photography, a plurality of 2-D views of the scene are taken from a number of horizontally spaced vantage points and the series of 2-D images is then compressed and printed at the focal plane of each of the lenticules of the lenticular screen to form a 3-D composite image of the field.
In the past, each of the plurality of compressed 2-D lineiform image bands occupied an equal width in the lenticule. Several images may be printed within a single band or a single image may be printed within a single band. This has commonly been referred to as W/N wherein "W" is the width of each lenticule and "N" is the number of 2-D image bands to be used in the total composition.
When a person is viewing a 3-D photograph, the ideal situation is for the eyes to see a stereo pair of adjacent 2-D lineiform image bands. Thus in referring to FIG. 1, the eye should see image bands 1 and 2, 2 and 3 or 3 and 4 so that the proper parallax between the pair of 2-D images can be maintained in order to reconstruct a 3-D image that is in focus and not blurred. Parallax is the apparent shift in position of an element of an object field due to the relative change in position of the element and the place from which the element is viewed. Because the eyes are frequently not in the right position, either because of distance from the photograph or the angle at which the photograph is viewed, the eyes will not always see the stereo pair formed by the adjacent 2-D image bands. Frequently, the eyes will see stereo pairs formed by 2-D image bands 1 and 3, 2 and 4 or 1 and 4 (FIG. 1) according to the angle and the distance of viewing the 3 -D photograph. When the eyes see a stereo pair where the lineiform image bands are not adjacent, they cannot fuse the two pairs of images together to form a solid image because of the excessive parallax.
In most lenticular screen type 3-D photographs, the maximum viewing angle of the lenticule of the print material is approximately 34.degree. due to the optical limitations within the system. Consequently, each compressed lineiform 2-D image band will cover an angle of approximately 81/2.degree. of the viewing angle of the lenticule with a stereo pair formed by adjacent 2-D image bands covering approximately 17.degree.. At a normal viewing distance of 12 inches, the eyes will cover an angle of approximately 12.degree. of the viewing angle of the lenticule. Unless the 3-D photograph is held exactly at the center of both eyes and perpendicular to the eyes, the eyes will see a stereo pair formed by image bands 1 and 3 or 2 and 4.